The present invention relates generally to osteoplasty and more particularly to a method and apparatus for introducing an immobilizing substance to a target site of a bone such as a vertebra to stabilize and repair fractures and the like in the bone.
Certain bone fractures, such as compressive fractures in vertebrae, frequently are unstable resulting in movement of fragments and pain. Such fractures typically are treated using open surgical procedures. Although these procedures vary, they generally require exposing the vertebra to remove the damaged bone and adjacent discs. Bone graft material or metal prostheses are introduced between the adjacent undamaged vertebrae after the bone and discs are removed. Plastic cement or harvested bone may also be introduced between the vertebrae to immobilize them and promote bone growth.
However, open surgical procedures cause significant trauma to surrounding tissue and increase the risk of complications such as infection compared to percutaneous techniques in which only a narrow instrument is inserted through the skin and soft tissue. Further, percutaneous techniques have the advantage of reducing the duration of both surgery and recovery times compared to open surgical procedures.
Among the several objects and features of the present invention may be noted the provision of a method and apparatus for repairing bone fractures, the provision of a method and apparatus which support and immobilize the bone, the provision of a method and apparatus which reduce trauma to surrounding tissue, the provision of a method and apparatus which reduce associated complications, and the provision of a method and apparatus which reduce surgery and recovery times.
Briefly, apparatus of this invention injects an immobilizing substance into a target site of a bone. The apparatus comprises a cannula having a bore for transporting the immobilizing substance to the target site of the bone when a leading end of the cannula is positioned adjacent the target site of the bone. The bore has a diameter of at least about three millimeters. In addition, the apparatus comprises a rotary cutter element removably attachable to the cannula for easing insertion of the cannula into position so the leading end of the cannula is positioned adjacent the target site of the bone and a connector attached to at least one of the cannula and the cutter element for releasably connecting the cutter element to the cannula during insertion of the cannula into position adjacent the target site of the bone. The apparatus also includes a handle attached to the cutter element for turning the cutter element to advance the leading end of the cannula into position adjacent the target site of the bone.
In another aspect, apparatus of this invention moves tissue away from a target site of a bone. The apparatus comprises a cannula having a bore extending through the cannula to a leading end positionable adjacent the target site of the bone and a tissue distraction device having a spreader mechanism adapted to move between a collapsed configuration in which the mechanism is sized and shaped to pass through the bore of the cannula and past the leading end to the target site and a deployed configuration in which the mechanism is enlarged thereby to move surrounding tissue away from the target site of the bone.
In yet another aspect, the present invention includes a method of injecting an immobilizing substance into a target site of a bone comprising the steps of connecting a cutter element to a cannula, rotating the cutter element and cannula to insert the cannula into position adjacent the target site of the bone, and removing the cutter element from the cannula. In addition, the method includes the step of inserting a tissue distraction device into the cannula. The tissue distraction device has a spreader mechanism for moving surrounding tissue away from the target site. Further, the method includes the steps of expanding the spreader mechanism to move the tissue away from the target site and injecting the immobilizing substance through the cannula to the target site.
Other objects and features of the present invention will be in part apparent and in part pointed out hereinafter.